In a prospective study of nonschizophrenic, nonaffective delusional psychoses, 46 patients are classified according to ICD-8, DMS-III, Kendler's criteria for delusional disorder, Opjordsmoen's criteria for reactive delusional disorder, and Jørgensen and Jensen's criteria for reactive delusional psychosis. No single diagnostic group includes all patients. About one third of the patients are employed continuously, and less than half the patients have weekly social contacts. At a 2-year follow-up, big differences are revealed between the diagnostic groups as regards (1) signs and symptoms (no signs and symptoms 0-70%), (2) work status (employed continuously 11-60%), and (3) social contacts (weekly social contacts 11-60%). An overwhelming minority (0-25%) have an overall good outcome. To improve the classification of nonschizophrenic, nonaffective delusional psychoses with poor outcome (paranoia) and good outcome (reactive delusional psychosis), a multiaxial and polydiagnostic approach is recommended.